Multiple misfire low compression

BRI MARTINO

MEMBER
1998 TOYOTA TACOMA
2.7L
4 CYL
4WD
MANUAL
260,450 MILES

Doing a diagnosis I had multiple misfires in cylinders one, two and three. Also was pointing to EGR and MAF sensor. Did a compression test and had 30 psi and cylinder one and two and 180 psi and cylinder three and four. I am trying to figure out what would cause the low compression and what my steps would be to remedy it.

Thursday, August 17th, 2017 AT 11:22 AM

2 Replies

KEN L

MASTER CERTIFIED MECHANIC
54,144 POSTS

Hello,

It sounds like you have a burnt valve which will need to have the head removed and a valve job done. To be sure you should do a leak down test which will determine where the compression is going.

My guess is the exhaust valve.

Please let us know what happens so it will help others.

Cheers, Ken

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Friday, August 18th, 2017 AT 11:47 AM

STEVE W.

MECHANIC
15,237 POSTS

So you have 30 psi in the front two cylinders and 180psi in the rear two?

If that is correct my thought would be that you have a blown head gasket between cylinders 1&2. A leak down test on cylinder 1 would confirm it because the air pressure would leak out through cylinder 2. Only way to repair it would be to pull the head and change the gasket.
I would pull the head and see what you have. If the engine was running OK prior to this with no odd sounds or issues then replace the gasket and replace any other seals on the way through.

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Friday, August 18th, 2017 AT 10:10 PM